"Karl's amazing. He's an avid reader. And he speaks about five different languages, so he'll be rattling English to you and French to somebody else, and German to somebody else, and then the phone rings and he's speaking in Italian," she said.
The actress also talked about her upcoming period drama "Anna Karenina", in which she stars in the titular role alongside Jude Law and Aaron Johnson, reported Femalefirst.
The movie centres on aristocrat Anna's life-changing affair with the wealthy Count Vronsky.
The actress says she took pity on co-star Law's daily transformation in hair and make-up.
"No wonder he kept that hat on. I'd get to the end of the day, take my make-up and wig off, and I'd look bad.
"He'd take the make-up and wig off and look brilliant. And everyone would say, 'Oh yeah! Good-looking man underneath!," she added.